The invention has applicaiton inter alia to conventional refrigeration systems. Such systems commonly comprise an evaporating heat exchanger in which a liquid refrigerant, such as trichlorodofluoromethane (commonly available under the trade mark FREON) is evaporated to draw heat from an air flow (or alternatively a water flow). A compressor receives spent gaseous refrigerant from the heat exchanger along a suction line and discharges a compressed liquid refrigerant along a high-pressure line. A condenser, which is essentialy a heat exchanger, draws heat from the compressed refrigerant. Water is often used as a heat exchange medium in the condenser. The cooled refrigerant is conveyed along a high pressure line to an expansion valve associated with the evaporating heat exchanger and discharged through a narrow orifice to evaporate the liquid refrigerant and produce a cooling effect.
For proper and efficient operation, a "liquid seal" must be formed in the high pressure line upstream of the expansion valve. Otherwise, the expansion valve discharges gaseous refrigerant, which produces no cooling effect. In such systems, the liquid seal must extend from the condenser to the expansion valve. In practical applications, the expansion valve and evaporating heat exchanger are remote from the compressor and condenser. A high-pressure line exceeding a hundred feet is not unusual. This produces a requirement for a very substantial charge of liquid refrigerant and induces large pressure drops along the high-pressure line. The compressor must be sized accordingly and requires larger operating currents for operation. Also, formation of gaseous components reduces the efficiency of the expansion valve cannot be realistically avoided. Friction between the liquid refrigerant and surfaces of the high-pressure line causes formation of such gases. As well, the high-pressure line often extends through warm environments, once again creating gaseous components.
In the prior art, a condenser had been proposed and used to eliminate the requirement for a liquid seal extending from the system condenser to the expansion valve. Such a prior art condenser is structured substantially like the condenser 10 illustrated in FIG. 2. It has a thermally-conductive housing 12 defining a reservoir 14 for accumulating liquid refrigerant, an inlet 16 for receiving a refrigerant flow from the high pressure line, and an outlet 18 for discharging liquid refrigerant to the expansion valve. The inlet 16 and outlet 18 are aligned for installation in a straight section of the high pressure line and are positioned at the very bottom of the reservoir 14 to ensure that the outlet 18 remains immersed in liquid refrigerant. A U-shaped conduit 20 receives a refrigerant flow from the inlet 16 and terminates blind-ended proximate to the inlet 16 end of the housing 12. It has apertures (only one apertures 22 specifically indicated) on both opposing lateral sides of the conduit 20 that discharge the received refrigerant flow into the reservoir 14. In use, the condenser 10 is positioned in the path of cold air discharged from the evaporating heat exchanger, to condense gaseous components of the refrigerant in the high-pressure line.
To operate properly, the condenser 10 must condense the gaseous refrigerant at a rate correspdoning to the rate at which the expansion valve discharges liquid refrigerant. This is difficult to achieve over a short flow path, particularly in response to a "thin" cooling medium such as air. In the prior art condenser 10, the lower arm of its internal U-shaped internal conduit 20 is apertured below the operating liquid level of the condenser 10, which must be above the outlet 18. It consequently discharges a very large part of the high-pressure stream of refrigerant gas into the condensed, liquid refrigerant that tends to accumulate at the bottom of the reservoir 14 and the rest of the refrigerant gas towards various locations about the housing 12. This does not provide for optimal condensing of gaseous components. If the system must be charged to maintain more liquid refrigerant in the high-pressure line to accommodate slow condensing, this defeats the object of reducing line losses and simply introduces a significant restriction to liquid flow and incidental load in the high-pressure line. Such prior art condensers have been known to lead to compressor failure.